Switchable-hydrophilicity solvent liquid-liquid microextraction versus dispersive liquid-liquid microextraction prior to HPLC-UV for the determination and isolation of piperine from Piper nigrum L.

Switchable-hydrophilicity solvent liquid-liquid microextraction and dispersive liquid-liquid microextraction were compared for the extraction of piperine from Piper nigrum L. prior to its analysis by using high-performance liquid chromatography with UV detection. Under optimum conditions, limits of detection and quantitation were found as 0.2-0.6 and 0.7-2.0 µg/mg with the two methods, respectively. Calibration graphs showed good linearity with coefficients of determination (R2 ) higher than 0.9962 and percentage relative standard deviations lower than 6.8%. Both methods were efficiently used for the extraction of piperine from black and white pepper samples from different origins and percentage relative recoveries ranged between 90.0 and 106.0%. The results showed that switchable-hydrophilicity solvent liquid-liquid microextraction is a better alternative to dispersive liquid-liquid microextraction for the routine analysis of piperine in food samples. A novel scaled-up dispersive liquid-liquid microextraction method was also proposed for the isolation of piperine providing a yield of 102.9 ± 4.9% and purity higher than 98.0% as revealed by NMR spectroscopy.

The effect of Colchicum pusillum in human colon cancer cells via Wnt/ß-catenin pathway.

OBJECTIVE: Colchicum pusillum belongs to the family Colchicaceae that particularly rich in tropolonic alkaloids. The aim of this study was to investigate the cytotoxicity and in vitro anticancer activity of Colchicum pusillum ethanolic extract on Colo-320 primer and Colo-741 metastatic colon adenocarcinoma cell lines. MATERIALS AND METHODS: Colchicum pusillum was collected and extracted with ethanol. Different concentrations of Colchicum pusillum extract were incubated for 24 h and 48 h with Colo-320 and Colo-741 cells. Cell growth and cytotoxicity were measured by 3­(4,5­dimethylthiazol­2­yl)­2,5­diphenyltetrazolium bromide (MTT) assays. Anticancer and antiproliferative activities of Colchicum pusillum were investigated by immunocytochemistry using antibodies directed against to ß-catenin, Ki-67, LGR-5 Ki-67, DKK1, Frizzled-4, Wnt4, Wnt7a and caspase3 in Colo-741 cells. RESULTS: All concentrations of Colchicum pusillum extract had toxic effect in Colo-320 cells. Because of this, we used Colchicum pusillum extract at 20 µg/ml for evaluate anticancer activities only in Colo-741 cells. As a result of immunohistochemical staining, ß-catenin, LGR-5 and caspase-3 immunoreactivities were significantly increased while Wnt7a immunostaining intensity was decreased in Colo-741 cells. Conclusion We conclude that Colchicum pusillum extract increased ß-catenin and LGR-5 via Wnt/ß-catenin pathway in colon cancer cells. Interestingly, it decreased other signaling molecule, Wnt7a which is assumed to play protective role during carcinogenesis. Also, it increased significantly caspase-3 immunoreactivity showing that apoptotic pathways were triggered.